Rail cars (e.g., covered hoppers, open hoppers, box cars, tank cars, autoracks, passenger cars, locomotives, and flat cars) transport a wide variety of materials, such as agricultural products (e.g., fertilizer), industrial products (e.g., sand, cement, petroleum coke products, dry petroleum products, limestone, soda ash and pot ash), foodstuffs (e.g., grain products, vegetables, sugar, flour, bentonite, sunflower seeds, and flax), animate objects, such live animals, and packaged goods, which typically leave a residue in the rail car when the bulk of these materials are removed from the rail car itself. Sugar, flour, and fertilizer, for instance, often stick to interior and exterior surfaces of rail cars. This residue contaminates future shipments and removing it is integral to preventing the contamination of future shipments, maintaining the overall condition of the rail car itself and complying with health code requirements and the like.
Traditional cleaning systems and methods for rail cars use liquid cleaning solutions to wash and clean rail cars, which pose a significant number of problems. Liquid cleaning solutions use considerable amounts of water. Liquid cleaning solutions are difficult to properly handle and control. Liquid cleaning solutions dissolve the remaining residue and impurities and subsequently carry these pollutants. In many cases, liquid cleaning solutions simply drain off rail cars and into the sewer system, the drainage system, or the railyard itself, which pollutes the environment. In other cases, liquid cleaning solutions drain into collecting ponds, which are used by some railroads, but handling the leftover sludge is a problem as well, as it cannot be recycled, separated, or easily disposed. In fact, in light of these environmental problems, government officials and agencies have encouraged the railroad industry to develop alternative procedures to clean rail cars and tightened regulations governing the disposal of liquid cleaning solutions. In addition, liquid cleaning solutions are difficult to handle, because they freeze at temperatures that commonly exist in Northern climates in the fall, winter, and spring seasons. Liquid cleaning solutions can also damage rail cars by seeping into various cracks and crevices and freezing and/or by rusting the actual rail car itself. Moreover, if possible, cleaning procedures and systems using liquid cleaning solutions must dry surfaces cleaned with liquid cleaning solutions with portable heaters and fans or by exposing the cleaned surfaces to the environment. Heaters and fans are expensive and cumbersome. Drying rail cars outside takes several days and enables insects and rodents to enter rail cars. In particular, canvass surfaces are extremely difficult to dry. If canvass surfaces are not completely dried, they provide a moist surface for mold, bacteria, and mildew. Finally, liquid cleaning solutions are generally ineffective in cleaning oily materials from rail cars. Liquid cleaning solutions that are effective in cleaning oily materials generally leave a residue that contaminates rail cars that must be removed as well.